STEERING, SUSPENSION SHAKING

2001 Infiniti QX • 136,000 miles

I have 2001 Infiniti QX4, 4WD. When I go over rough spots in the road or a bump, my steering wheel shakes from side to side and the front end feels as if it is "crabing" or skittering across the roadway. This continues for a moment and then steering returns to normal. I suspect that it is worn ball-joints but am uncertain about other steering/suspension components that may be contributing.